Micro chip device

ABSTRACT

Buffer solution and blood are streamed in a channel of a micro chip so as to form layers. Aggregation inducing agent for aggregating platelets in blood is coated at a wall face on a buffer solution streaming side. If streaming amount of blood is increased in this state, a layer width of blood can be increased, and detail analysis between the aggregation inducing agent and the platelets is possible thereby. Even if it is necessary to take an image or a moving image for comparison between a pre-aggregation state and an aggregation state, it is sufficient to take only a portion where the aggregation inducing agent is coated, that is, a reaction portion. Then, a device can be made cheaper without two cameras or a moving mechanism for the camera or a micro chip.

BACKGROUND OF THE INVENTION

This invention relates to a micro chip device for properly controlling a reaction between specific solution and drug.

Classically, a reaction of some specific solution with some specific drug is caused in order to compare between a pre-reaction state and reaction state (see a Japanese patent application publication number of which is 2005-17254).

If a coagulant (a reagent which induces the platelet aggregation) is added to blood, for instance, it is generally known that platelets in blood and the coagulant interact, and aggregation occurs thereby. In order to quantify a degree of platelet aggregation in such a case, platelet aggregation ability should be evaluated in such a way that blood which has not yet respond to the coagulant is adopted for a reference, and aggregation which occurs by reaction between the blood and the coagulant is measured and is compared with the reference. In the past, a device for executing aggregation reaction in a micro channel in the micro chip in order to measure the platelet aggregation ability has been proposed. For example, at least two channels wherein blood flows are formed in the micro chip, and coagulant is coated in one channel so that blood and coagulant can interact, and coagulant is not coated in the other channel so as to watch pre-aggregation state of the blood. It is necessary to observe simultaneously with comparing two channels in such a device.

In such a device having two channels, it may be necessary to take images or sequential images (moving images) of the respective channels for comparison between a reaction state and a pre-reaction state. One option for doing so is to arrange one camera for each channel, and the other option is to arrange only one camera and to make the camera or the micro chip movable. In any case, defects are that the structure is complex and the device is rather expensive. Especially, in the second option, some mechanism for moving the camera or the micro chip is necessary, and troubles on the operation are anticipated.

When excessive solution flows into the channel wherein drug is coated, proper reaction state may not be obtained. If excessive blood flows into the channel wherein the coagulant is coated for instance, it is difficult to quantify due to clogging of the channel with platelets aggregated at one time.

The object of the invention is to provide a micro chip device for solving the above-mentioned problem

SUMMARY OF THE INVENTION

One aspect of the invention is a micro chip device, comprising:

a first channel wherein first solution flows;

a second channel wherein second solution flows;

a third channel connected with a downstream of said first and second channels wherein said first and second solutions flow, forming layers;

first solution supply means for controlling supply amount of said first solution;

second solution supply means for controlling supply amount of said second solution; and

a reaction portion located at said third channel which does not react to said first solution but reacts to said second solution.

And, another aspect of the invention is the micro chip device, wherein an interface between said first and second solutions moves in said third channel on the basis of a control of supply amount of said first solution by said first solution supply means and a control of supply amount of said second solution by said second solution supply means.

And, another aspect of the invention is the micro chip device, wherein said reaction portion is located at a wall face which contacts with said moving interface.

And, another aspect of the invention is the micro chip device, wherein sections of said first through third channels have almost rectangular shapes.

Besides, another aspect of the invention is the micro chip device, wherein said reaction portion is an area where drug which does not react to said first solution but reacts to said second solution is coated.

According to these aspects of the invention, both states, the state where the second solution does not respond to the reaction portion and the state where the second solution starts to respond to the reaction portion, can be switched by controlling respective layer widths of the first and second solutions in the third channel with both the first and second solutions supply means. Then, both states, the state where the second solution does not respond to the reaction portion and the state where the second solution starts to respond to the reaction portion, can be watched at the same portion, and detail analysis is possible thereby in comparison with a case of watching at different portions. And, it is sufficient to take only a reaction portion and is not necessary to provide two cameras or a moving mechanism for the camera or a micro chip even if an image or a moving image is necessary to be taken for comparison between a pre-reaction state and a reaction state. For this reason, the device can be made cheaper.

Furthermore, another aspect of the invention is the micro chip device, wherein said first solution is buffer solution, and said second solution is blood, and said drug is aggregation inducing agent for aggregating platelets in said blood.

According to this aspect of the invention, it is possible to watch a pre-aggregation state of platelets and a way of aggregating platelets, so that detail analysis, such as an analysis how to change a size, an area or volume of lump aggregation with time, is possible. Even if an image or a moving image is necessary to be taken for comparison between an aggregation state and a pre-aggregation state, it is sufficient to take only a portion on which the aggregation inducing agent is coated (that is, the reaction portion) without arranging two cameras and without a moving mechanism of a camera or a micro chip, and a stabilization at the time of operations can be improved and the device can be made cheaper due to its simplified structure.

BEST MODE FOR EXECUTING THE INVENTION

The invention utilizes a characteristic of fluid flowing in a micro channel of a micro chip, the characteristic wherein if two kinds of solutions or more are streamed in a micro section of channel, these solutions flow without mixing with each other, forming layers, due to very low Reynolds number. Concretely speaking, the first and second solutions are streamed in a micro channel so as to form layers, a reaction portion which reacts to only the second solution is located at a predetermined area, so that the reaction state between the second solution and the reaction portion can be fine controlled in the area where the reaction is located by changing the layer widths of the first and second solutions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top view for explaining one instance of the whole structure of a micro chip device according to the invention;

FIG. 2 is an enlarged view of a state of a periphery of a meeting portion of FIG. 1;

FIG. 3 is an enlarged top view showing a H portion of FIG. 1;

FIG. 4 is a sectional view taken as indicated by line I-I of FIG. 1;

FIG. 5 is a sectional view showing an instance of location of a reaction portion G;

FIG. 6 is a top view for explaining another instance of the whole structure of the micro chip device according to the invention; and

FIG. 7 is a top view for explaining another instance of the whole structure of the micro chip device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The best mode of embodiment for executing the invention is now explained, referring to the appended FIGS. 1 through 4. FIG. 1 is a top view for explaining one instance of the whole structure of a micro chip device according to the invention, FIG. 2 is an enlarged view of a state of a periphery of a meeting portion of FIG. 1, FIG. 3 is an enlarged top view showing a H portion of FIG. 1, and FIG. 4 is a sectional view taken as indicated by line I-I of FIG. 1.

A micro chip device A₁ according to the invention has a chip body M₁ which is comprised of a first channel B₁ wherein first solution (denoted by D₁ of FIG. 2) flows and a second channel B₂ wherein second solution (denoted by D₂ of FIG. 2) flows, as shown in FIG. 1 and FIG. 2. Both channels B₁ and B₂ are located so as to meet with each other at a downstream side (“the meeting portion” hereinafter denoted by C) of both channels, and a third channel B₃ is connected with both channels B₁ and B₂ at the downstream thereof. The first solution D₁ which is supplied from the first channel B₁ to the third channel B₃ and the second solution D₂ which is supplied from the second channel B₂ to the third channel B₃ respectively flow, forming two layers without mixing with each other due to micro sections of the channels B₁, B₂ and B₃. A reaction portion G which reacts to only second solution D₂ and does not react to the first solution D₁ is arranged in the third channel B₃ (see G of FIG. 2( a) and (b)).

In this embodiment, supply amount of the first solution D₁ is controlled by first solution supply means and supply amount of the second solution D₂ is controlled by a second solution supply means. Respective layer widths W₁ and W₂ in FIG. 2( a) of the solutions D₁ and D₂ in the third channel B₃ depend on amount of flow, pump pressure or viscosity thereof, and are controlled on the basis of a control of the supply amount of the first solution D₁ by the first solution supply means and a control of the supply amount of the second solution D₂ by the second solution supply means. According to both controls, an interface E (see FIG. 2( a), (b)) between the first solution D₁ and the second solution D₂ in the third channel B₃ moves. FIG. 2( a) shows such a state that the interface E is at an almost center, and FIG. 2( b) shows a state of the interface E moved upward. This movement of the interface E induces a state as shown in FIG. 3( a) wherein the reaction portion G contacts with only first solution D₁ and does not contact with the second solution D₂, a state as shown in FIG. 3( b) wherein the second solution D₂ starts to contact with the reaction portion G, and a state as shown in FIG. 3( c) wherein all reaction portion G contacts with the second solution D₂.

The solution supply means for controlling the layer widths W₁ and W₂ of the first and second solutions D₁ and D₂ may be a pressure pump P₁ of FIG. 1 which is located at the first channel B₁ and a pressure pump P₂ of FIG. 1 which is located at the second channel B₂, or may be ones as shown in FIG. 6. That is, the downstream of the third channel B₃ may be branched into a fourth channel B₄ which is located on a side where the first solution D₁ flows and a fifth channel B₅ which is located on a side where the second solution D₂ flows, and the pressure pump P₁ as the first solution supply means may be located at the first channel B₁ and a first withdrawal pump P₁ as the second solution supply means may be located at the fifth channels B₅. Furthermore, the pressure pump P₂ (see FIG. 1) as the second solution supply means may be located at the second channel B₂ and a second withdrawal pump (not shown) as the first solution supply means may be located at the forth channels B₄. Otherwise, the pressure pump P₁ as the first solution supply means may be located at the first channel B₁, and the first withdrawal pump P₃ as the second solution supply means may be located at the fifth channel B₅, and a second withdrawal pump P₄ as the first solution supply means may be located at the forth channel B₄, as shown in FIG. 7.

According to the invention, a person can watch both states, the state as shown in FIG. 3( a) wherein the second solution D₂ does not react to the reaction portion G, and the state as shown in FIG. 3( b) and (c) wherein the second solution D₂ is reacting to the reaction portion G at the same portion, so that detail analysis is possible in comparison with a case of watching at different portions. Even if an image or a moving image is necessary to be taken for comparison between a reaction state and a pre-reaction state, it is sufficient to take only the reaction portion G without arranging two cameras and without a moving mechanism of a camera or a micro chip (that is, the above-mentioned chip body), and a stabilization on operations can be improved and the device can be made cheaper due to its simplified structure.

Preferably, the reaction portion G is located at a wail face which contacts with the moving interface E.

Preferably, the sections of the first through third channels B₁ through B₃ respectively have rectangular shapes (the width and the height may be tens of μm through hundreds of μm or so) as shown in FIG. 4, and the reaction portion G is located at the wall face of the third channel B₃ (Preferably, the wall face is a moving one, contacting with the interface E and includes a wall face Ba close to an observer K and a wall face Bd far from an observer K).

Besides, the reaction portion G may be an area coating drug thereon which does not react to the first solution D₁ but reacts to only the second solution D₂.

The first solution D₁ may be buffer solution, and the second solution D₂ may be blood, and the drug may be aggregation inducing agent for aggregating platelets in the blood. Then, it is possible to watch a pre-aggregation state of platelets and a way of aggregating platelets, so that detail analysis, such as an analysis how to change a size, an area or volume of lump aggregation with time, is possible. Even if an image or a moving image is necessary to be taken for comparison between an aggregation state and a pre-aggregation state, it is sufficient to take only a portion on which the aggregation inducing agent is coated (that is, the reaction portion G) without arranging two cameras and without a moving mechanism of a camera or a micro chip, and a stabilization at the time of operations can be improved and the device can be made cheaper due to its simplified structure.

First Embodiment

In this embodiment, the micro chip device A₁ as shown in FIG. 1 was made. B₁ in the figure denotes the first channel wherein buffer solution (the first solution D₁ of FIG. 2) flows, and B₂ denotes the second channel wherein blood (the second solution D₂ of FIG. 2) flows, and B₃ denotes the third channel connected with the downstream of these channels. These three channels B₁ through B₃ are arranged in the shape of a Y character. The first pressure pump P₁ (the first solution supply means) for supplying the buffer solution D₁ is connected with the upstream of the first channel B₁, and the second pressure pump P₂ (the second solution supply means) for supplying the blood D₂ is connected with the upstream of the second channel B₂.

These three channels B₁ through B₃ respectively have rectangular shapes in their sections as shown in FIG. 4, each width Wa of the first and second channels B₁, B₂ is 100 μm and each height h of both is 50 μm, and the width Wa of the third channel B₃ is 200 μm and the height h is 50 μm.

A water-soluble polymer derived from 2-methacryloyloxy ethyl phosphorylcholine (MPC) is a compound, which has the similar structure as the polar group of phospholipid in cell membrance.

Various Materials

Nonabsorptive substance can be obtained with using MPC, which does not absorb protein, such as a product manufactured by AI BIO-CHIPS Co., Ltd. under the name of “PC-modifier-PDMS”, is coated on the upper wall face Ba and side wall faces Bb, Bc, and nonabsorptive substance, such as a product manufactured by AI BIO-CHIPS under the name of “PC-modifier-C”, is coated on the lower wall face Bd. In this embodiment, the blood D₂ supplied from the first channel B₁ to the third channel B₃ and the buffer solution D₁ supplied from the second channel B₂ to the third channel B₃ flow, forming layers without mixing with each other.

And, substance having affinity for living body is coated in advance on a 50 μm×50 μm square area denoted by G of FIG. 5 which is 20 μm far from the side wall face Bc on the lower wall face Bd of the center portion of the third channel B₃, and thereafter the aggregation inducing agent is coated thereon.

If the supply amount of the blood D₂ and the supply amount of the buffer solution in are made almost equal by adjusting the first and second pressure pumps P₁ and P₂, the layer width W₁ of the blood D₂ and the layer width W₂ of the buffer solution D₁ in the third channel D₃ are almost made equal as shown in FIG. 2( a) and FIG. 3( a), and the aggregation inducing agent G does not contact with the blood D₂, but contacts only the buffer solution D₁. Therefore, no reaction occurs between the blood D₂ and the aggregation inducing agent G. But, so-called spontaneous platelet aggregation wherein platelets aggregate even if aggregation inducing agent is not added can be watched, depending on a characteristic or a state of a blood sample since rate of flow is higher as a distance from the wall face becomes longer and shear stress is applied on blood sample.

If the supply amount of the buffer solution D₁ is decreased and the supply amount of the blood D₂ is increased in the afore-mentioned state, the interface E ascends as shown in FIG. 3( b), and a part of the aggregation inducing agent G starts to contact with the blood D₂ and a small amount of aggregation starts to occur.

If the supply amount of the blood D₂ is further increased, the state changes as shown in FIG. 3( c) and all face of the aggregation inducing agent G contacts with the blood D₂. Then, the aggregation reaction becomes stronger.

Second Embodiment

In this embodiment, a micro chip device A₂ as shown in FIG. 6 was made. M₂ in FIG. 6 denotes a chip body, B₁ in FIG. 6 denotes the first channel wherein buffer solution (the first solution D₁ of FIG. 2) flows, and B₂ denotes the second channel wherein blood D₂ (the second solution of FIG. 2) flows, and B₃ denotes the third channel connected with the downstream of these channels. And, the downstream of the third channel B₃ may be branched into the fourth channel B₄ which is located on a side where the buffer solution D₁ (upper side in the figure) flows and the fifth channel B₅ which is located on a side where the blood D₂ flows (lower side in the figure), and the pressure pump P₁ as the first solution supply means is located at the first channel B₁ and the first withdrawal pump P₃ as the second solution supply means is located at the fifth channel B₅ through a sealed container L₁. When air in the sealed container L₁ is sucked by the first withdrawal pump P₃, the solution flows from the fifth channel B₅ into the sealed container so as to be pooled in the container. With such a structure, the blood D₂ itself does not flow inside the first withdrawal pump P₃, so that there is no clogging with blood cells in a movable portion inside the pump. As the result, it is possible to avoid a trouble, a damage, a breakdown of the pump.

These five channels B₁ through B₅ respectively have rectangular shapes in their sections as shown in FIG. 4, the width Wa of the third channel B₃ is 200 μm and the height h thereof is 50 μm. In the other channels, the width Wa is 100 μm and the height h is 50 μm. Nonabsorptive substance which does not absorb protein, such as a product manufactured by AI BIO-CHIPS Co., Ltd. under the name of “PC-modifier-PDMS”, is coated on the upper wall face Ba and side wall faces Bb, Bc of each channel, and nonabsorptive substance, such as a product manufactured by AI BIO-CHIPS Co., Ltd. under the name of “PC-modifier-C”, is coated on the lower wall face Bd.

And, substance having affinity for living body is coated in advance on a 50 μm×50 μm square area denoted by G in FIG. 5 which is 20 μm far from the side wall Bc on the lower wall Bd of the center portion of the third channel B₃, and thereafter the aggregation inducing agent is coated thereon.

When the pressure pump P₁ is firstly operated in such a device, the first channel B₁, the third channel B₃, the fourth channel B₄ and the fifth channel B₅ are filled with the buffer solution D₁. When the first withdrawal pump P₃ is operated in the afore-mentioned state, the suction force acts even in the blood D₂ in the second channel B₂ through air in the sealed container L₁→the buffer solution D₁ in the fifth channel B₅→the buffer solution D₁ in the third channel B₃. As the result, the buffer solution D₁ in the fifth channel B₅ and the buffer solution D₁ in the third channel B₃ are ejected into the container L₁. With this ejection, the blood D₂ is supplied from the second channel B₂ to the third channel B₃, and flows so as to form a layer. Thereafter, the blood D₂ is ejected from the fifth channel B₅ into the container L₁. The layer width W₁ of the buffer solution D₁ and the layer width W₂ of the blood D₂ can be changed by adjusting pressurized amount of the buffer solution D₁ by the pressure pump P₁ and suction amount of the blood D₂ by the first withdrawal pump P₃. Preferably, the pressurized amount of the pressure pump P₁ may be gradually decreased with constant suction amount with the first withdrawal pump P₃.

Third Embodiment

In this embodiment, a micro chip device A₃ as shown in FIG. 7 was made. The chip body M₂ the same as one of the second embodiment is used, and a valve V for controlling supply of blood is located at the second channel B₂, and the second withdrawal pump P₄ as the first solution supply means is connected with the fourth channel B₄ through a sealed container L₂. Similar to the second embodiment, the pressure pump (the first solution supply means) P₁ is connected with the first channel B₁, and the sealed container L₁ and the first withdrawal pump (second solution supply means) P₃ are connected with the fifth channel B₅.

If the valve V is closed and the respective withdrawal pumps P₃ and P₄ are stopped and only the pressure pump P₁ is operated in such a device, the first channel B₁, the third channel B₃, the fourth channel B₄ and the fifth channel B₅ are filled with the buffer solution D₁, similar to the second embodiment. When both withdrawal pumps P₃ and the P₄ are operated in the afore-mentioned state, the suction force acts even on the blood D₂ in the second channel B₂ through air in the sealed containers L₁ and L₂→the buffer solution D₁ in the fifth channel B₅ and the fourth channel B₄→the buffer solution D₁ in the third channel B₃. If the valve is opened and the pressurized amount by the pressure pump P₁ is reduced up to some constant one, the buffer solution D₁ in both channels B₄ and B₅, and the buffer solution D₁ in the third channel B₃ are ejected into the containers L₁ and L₂. With such an ejection, the blood D₂ is supplied from the second channel B₂ to the third channel B₃, and flows, forming a layer. Thereafter, the blood D₂ is ejected from the fifth channel B₅ into the container L₁. The layer width W₁ of the buffer solution D₁ and the layer width W₂ of the blood D₂ can be changed by adjusting the suction amount of the blood D₂ by the first withdrawal pump P₃ and suction amount of the buffer solution D₁ by the second withdrawal pump P₄. Otherwise, the channel width of the buffer solution D₁ flowing in the first channel B₁, the third channel B₃ and the fourth channel B₄ may be adjusted with both withdrawal pump P₃ and the pressure pump P₁ by simultaneously operating the pressure pump P₁ with the withdrawal pumps P₃ and P₄.

The present invention has been explained on the basis of the example embodiments discussed. Although some variations have been mentioned, the embodiments which are described in the specification are illustrative and not limiting. The scope of the invention is designated by the accompanying claims and is not restricted by the descriptions of the specific embodiments. Accordingly, all the transformations and changes within the scope of the claims are to be construed as included in the scope of the present invention. 

1. A micro chip device, comprising: a first channel wherein first solution flows; a second channel wherein second solution flows; a third channel connected with a downstream of said first and second channels wherein said first and second solutions flow, forming layers; first solution supply means for controlling supply amount of said first solution; second solution supply means for controlling supply amount of said second solution; and a reaction portion located at said third channel which does not react to said first solution but reacts to said second solution.
 2. The micro chip device according to claim 1, wherein an interface between said first and second solutions moves in said third channel on the basis of a control of supply amount of said first solution by said first solution supply means and a control of supply amount of said second solution by said second solution supply means.
 3. The micro chip device according to claim 2, wherein said reaction portion is located at a wall face which contacts with said moving interface.
 4. The micro chip device according to claim 3, wherein sections of said first through third channels have almost rectangular shapes.
 5. The micro chip device according to claim 1, wherein said reaction portion is an area where drug which does not react to said first solution but reacts to said second solution is coated.
 6. The micro chip device according to claim 5, wherein said first solution is buffer solution, and said second solution is blood, and said drug is aggregation inducing agent for aggregating platelets in said blood. 